My new collapsible Summicron

[payasam]

First, can someone date my collapsible Summicron, serial number 1218627?

Second, does the attached photo seem reasonable for this lens at f/4 (1/30 sec., Fujicolor 400)?

I'm struggling to get to know this lens and an M2, both bought recently from Youxin Ye. At this time, accuracy of focus at close distances is somewhat doubtful, specially with fast lenses wide open.

[Brian Sweeney]

You need to shoot some wide-open to test the focus, and probably post some center-shot highlights. My Collapsible Summicron's are all accurate wide-open at F2. At F4, they are superb.

I'm planning on testing my F2 lenses, or at least some of them, today. Wish it was spring. Better for testing.

[payasam]

Thanks, Brian. I have taken several frames at f/2; but there are many imponderables and I have still to come to conclusions.

[dannynono]

If your still getting to know the camera and lens combo, you may want to shoot any focus test shots with the camera mounted on a tripod. otherwise, it may be hard to differentiate between lens issues and user issues.

[Photon42]

Hi paysam,

summilux.net has got a 'dating service'

rgds
Ivo

[ferider]

Originally Posted by payasam

First, can someone date my collapsible Summicron, serial number 1218627?

1954, Mukul. Congrats on the combo.

Regarding the picture, your camera might be off. Summicrons being off is much rarer. Best to compare lens focus scale on the camera focused at close distance with a tape measure. Could be camera shake, too, though.

Roland.

[45-Otto]

Leica lens date list I have dates this lens as produced in 1954.

[Brian Sweeney]

It's easy to knock a Summicron's focus off when re-assembling it after a cleaning. The elements are a very tight fit into the metal. I've had to use much more force with the Coll. Summicron and Type I Rigid Summicron than with other lenses. I've re-assembled a lens and had it's focus off: the second group had to be PUSHED back into place. After that, no problems. It finally "clicked" into place. Fraction of a millimeter. The first test roll revealed a problem with anything not at 4ft. At 4ft, I got a beautiful portrait, however.

[payasam]

Harland, thanks. The crucial test shots were with the camera resting on a table-top.

Ivo, Roland, Otto, thank you all. Roland, I was about to do the tape measure thing but thought I'd check e-mail first.

Brian, I do not know if this lens has been dismantled. Certainly I don't intend to take it apart and put it together again.

If I identify focus errors, I can compensate when using the lens. Had an M3 for 17 years whose R/F was off, and I habitually mis-focussed to get focus right.

[payasam]

It is now confirmed that both the Summicron and the M2 are OK for focus. I used the Summicron and an Industar 61 L/D at full aperture and closest focus. Here is a crop, not sharpened, of the Summicron photo. Focus was on "JESSOP", with the blue carton closer to the camera and the green one farther from it. Camera was steady on table top. Other Summicron pictures on the roll are consistent with this conclusion. The Industar at f/2.8 is easily more contrasty than the Summicron at f/4, incidentally.

[Solinar]

Originally Posted by payasam

The Industar at f/2.8 is easily more contrasty than the Summicron at f/4, incidentally.

The Industar is great to shoot winter scenes with at the Finnish border, especially at this time of year. While I like the look of Ingmar Bergman's B/W "The_Seventh_Sea"l, portraits of people deserve a Summicron.

[payasam]

Vic, thank you.

[Brian Sweeney]

Is this the $60 Summicron that you posted about on the other trhead?

The I-61L/D does have more contrast than the Collapsible Summicron, and more than the First Rigid. The Leica lenses of the 50s are more "Kodachrome" colors.

ANYWAY! My "close to perfect" Sumicron, wide-open:



From this thread:
http://www.rangefinderforum.com/foru...ad.php?t=53444

I'll have a "direct compare" between this lens and the Coll. Summicron that i recoated myself next week. The latter lens does better than I tought it ever would.

[sanmich]

Originally Posted by Brian Sweeney

... the Coll. Summicron that i recoated myself next week.

Hi Brian

You recoat lenses by yourself???

please tell us more!

Michael

[payasam]

Yes, Brian, the same. If the weather in Delhi improves, I shall do some outdoor shots and maybe post a couple.

[Brian Sweeney]

My "famous cheeze-wiz As Seen On TV Summicron repair"- See this thread for pictures of the lens and sample photographs with it.


http://www.rangefinderforum.com/foru...epair+eyeglass

[payasam]

Thanks, Brian.
Roland, I did a tape measure test. At 3.5, 4 and 4.5 feet, the Summicron's distance scale showed a distance slightly less than the measured distance. At 4.5 feet, for example, the scale showed just over 4 feet. My Industar 61 L/D, by contrast, was bang on at 1.1 m and 1.5 m.
Hopelessly confused old man now.

[Brian Sweeney]

If you have a tripod, set the camera up on it and try some test pictures. I use a fence post, so i can see how far off the focus might be. Try test close-up and at infinity. It is the difference between the "shim" or RF cam being off (optics to film plane off), or a lens element being out of position (wrong focal-length).

[payasam]

If I were to do the tripod thing, Brian, I would have the lens axis at an oblique angle to the fence (or railings or whatever). I assume that is what you mean.

Here are two pictures taken with the lens at the same time, one at f/2 and the other at f/5.6. Both prints scanned in the same pass, nothing done other than cropping and -- to take care of the different colour casts the lab had managed -- desaturating.

[payasam]

Thanks again, Vic.

[ferider]

Originally Posted by payasam

Roland, I did a tape measure test. At 3.5, 4 and 4.5 feet, the Summicron's distance scale showed a distance slightly less than the measured distance. At 4.5 feet, for example, the scale showed just over 4 feet. My Industar 61 L/D, by contrast, was bang on at 1.1 m and 1.5 m.

:

If I were to do the tripod thing, Brian, I would have the lens axis at an oblique angle to the fence (or railings or whatever). I assume that is what you mean.

Here are two pictures taken with the lens at the same time, one at f/2 and the other at f/5.6. Both prints scanned in the same pass, nothing done other than cropping and -- to take care of the different colour casts the lab had managed -- desaturating.

Hi Mukul,

half a foot or less is not so bad for a 50/2 wide open. Only a film test will show if there is a real problem.

For final collimation check, I usually do boring stuff like this:



Have to use a tripod though to avoid body back-lash.

But looking at your last f2 photo, I feel there might be another issue. Eyes are pretty much in focus, but the Summicron should produce a clearer picture. Can you check for haze with flashlight ?

AFAIK, Youxin does only CLA mechanics of a lens, not the optics.

Best,

Roland.

[Tom A]

You can also check the focus on the 50/2-M2 by putting the camera on a tripod, removing the back door (or just flipping it up). Put a piece of ground glass on the rails and focus through it. You can also use a piece of "drafting Mylar" a semitransparant film used for preciscion drafting. Use a measuring tape and set the lens at 1meter and look through it on the "ground glass" Set the camera on B and use a cable release with a locking screw on it or volunteer somebody to hold the release down while you are checking - it is an operation that requires at least three hands!. Is it sharp or is the focus off?
Remember that when you measure, You have to measure from the filmplane (about 5 mm from the back edge of the camera).
The 50 collapsible Summicron can be tricky. It is inherently a low contrast lens (compared to later ones) and that gives it a bit softer look and that can be viewed as "fuzzy" focus occasionally.
Once you got confirmation that your focus is "on". Get a roll of film and load up and shoot it of the same subject. Work through your apertures from f2 to f16 and once you have developed the film you can check sharpness and focus again. This will also tell you if there is any focus shift when you stop down.

[Brian Sweeney]

Honestly, the two portraits look pretty good, especially for a $60 lens! The front has some marks, use a shade. Get a clip-on until you fix that rim-ding. Also, check the interior elements for haze with a flashlight.

[Gabriel M.A.]

Originally Posted by Tom A

You can also check the focus on the 50/2-M2 by putting the camera on a tripod, removing the back door (or just flipping it up). Put a piece of ground glass on the rails and focus through it. You can also use a piece of "drafting Mylar" a semitransparant film used for preciscion drafting.

I've found that there is a variation between different ground glass when doing this. I'm not very knowledgeable on the optics/physical reason behind this, but empirically, I've experienced some glass to be more reliable than others. I think if your glass is too thick, you may be mislead into adjusting the lens out of focus.

I don't know if what I just "said" made any sense, but what I'm trying to get to is that if you use some clear film (like developed, unexposed B&W film) and use that instead, it would be the best way to check collimation/focus on lenses with "fast" apertures (f/2 or larger).

Or am I just unwittingly perpetuating one of those Internet myths?

[Tom A]

Gabriel, it is a bit of both. If your groundglass is to thick it can affect your focus-plane. Usually not enough to worry about with most lenses though (Noctilux@f1 at 1 meter yes, but a Summicron f2 no). This is why suggest the Mylar instead as it is closer to the thickness of a film. I simply tape it on the rails and use it like that. The problem is that however may times you do it - the damned lens is going to do what it wants! Sometimes a lens that works fine at 1m, will through focus at 2m or even 5 meter. You have to check, shoot, realign and pray that everything stays fine. The only time I really set myself to do this rather boring task is with fast lenses, Noctilux, Summilux 75, Nokton 35f1.2. Of course, you also have to dedicate a camera body to it for these lenses as even miniscule shifts in filmplane/lens will affect it.
Ow, to hell with it and stop down or get f2 -f2.8 lenses instead!